1. Field of the Invention
This invention relates to pipe; and, more particularly, it relates to conduit means having a plurality of longitudinally extending passageways.
2. Description of the Prior Art
Conduit means, or pipe, has been used for a wide variety of purposes. One fairly recent innovation that has increased with the advent of underground utilities has been the use of short sections of concrete pipe having a plurality of longitudinally extending passageways. The concrete sections had to be short, since they were so difficult to handle. They were heavy, frangible in the sense of being easily broken when dropped, expensive and inflexible; and were laboriously and expensively joined together because of the large number of joints required to join the short sections into long expanses. Moreover, each of the joints required hand application of an adhesive material to join the sections, further adding to the expense of the installation. Also, the concrete pipe sections were relatively costly to form.
Because of these disadvantages, there has been a more recent increased use of single passageway plastic pipe to replace the concrete because of the obvious advantage of its longer length, light weight and less costly pipes and its less expensive installation. When a plurality of longitudinally extending passageways were desired, the plastic pipes were assembled, or banded together to form bundles. Although advantageous, these bundles were costly to assemble and difficult to install; particularly when joining together longitudinally or making turns, as by elbows; commonly called sweeps.
An attempt has been made to reach a compromise by employing short sections of conduit having a plurality of passageways all having external walls and incorporating lateral structural supports, or ribs, to achieve strength for supporting the external loads. Such plastic conduit were formed by injection molding in short sections. While a large number of pieces of the conduit could be handled on a truck and were advantageous from this point of view, the short sections again necessitated a large number of joinings and joints to form the desired underground conduit.
Thus, it can be seen that the prior art has not provided pipe that has the following desirable features:
1. PIPE THAT CAN BE ECONOMICALLY AND CONTINUOUSLY EXTRUDED FOR ECONOMY;
2. PIPE THAT HAS THE STRENGTH AND ECONOMY OF MANUFACTURE SO AS TO BE EMPLOYED IN MORE ELONGATE SECTIONS AND REDUCE THE COST OF INSTALLATION; AND
3. EXTRUDABLE PLASTIC PIPE THAT NOT ONLY HAS THE DESIRED IMPERMEABILITY AND IMPERVIOUSNESS, RESISTS CORROSION OVER A LONG PERIOD OF TIME BUT ALSO HAS THE HIGH BURST AND EXTERNAL LOAD BEARING STRENGTH TO ENABLE DIRECT INSTALLATION IN SUBTERRANEAN LOCATIONS.